Add-onAny add on to share PDFs / documents easily ?

Active member

Is there any add on by which PDFs / documents can be shared easily ? The PDF can be easily categorized, rated with stars etc. More like shop with every stuff is free

If there are no such plugins, then, I'd like to create one for me :

I have a forum related to books & reading. I'd like to have a download section where books can be shared easily. Only public domain books & no piracy. I will just share direct download links of FeedBooks or Gutenberg [if that is illegal, then I will host them on my server]. It must be easy for admins to add books.